Probe for use in measuring apparatus

• US 4,360,973 A
• Filed: 05/26/1981
• Issued: 11/30/1982
• Est. Priority Date: 12/24/1976
• Status: Expired due to Fees

• Current Assignee: Renishaw PLC
• Original Assignee: Renishaw Electrical Limited (Renishaw PLC), Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: McMurtry, David R.
• Primary Examiner(s): Little, Willis
• Application Number:
  US06/267,068
• Time in Patent Office: 553 Days
• Field of Search: 33/174 L, 33/174 R, 33/174 P, 33/169 R, 33/172 E, 33/148 H, 33/149 J
• US Class Current: 33/561
• CPC Class Codes: G01B 7/012 Contact-making feeler heads therefor

Abstract

A probe for use in measuring apparatus has a base member including a two-dimensional seat for an intermediate member which, in turn, includes a two-dimensional seat for a stylus holder. The two seats face in opposite directions so that the stylus holder can be displaced from the seated position in either of two opposite directions.

Claims

1. A device for mounting a stylus in positioning-determining apparatus wherein said device and an object are movable relative to each other for engaging the stylus with the object thereby to sense the position thereof, said device comprising a base member having a first two-dimensional seat thereon, an intermediate member, first bias means connected to the base member and the intermediate member to urge the intermediate member into engagement with the first seat thereby to support the intermediate member on the first seat in a rest position, the intermediate member being tiltable on, and being linearly separable from, the first seat when disposed from said rest position in opposition to the first bias means, a second two-dimensional seat provided on the intermediate member and facing in a direction opposite to that in which the first seat faces, a stylus holder to which a stylus is connectable, a second bias means connected to the stylus holder and the intermediate member to urge the stylus holder into engagement with the second seat thereby to support the stylus holder on the second seat in a rest position, the stylus holder being tiltable on, and being linearly separable from, the second seat when displaced from said rest position in opposition to the second bias means, and means for providing a signal when said stylus engages the object.

2. A device according to claim 1, further comprising an axisymmetric arrangement of support members defining said first seat, the intermediate member includes an axisymmetric arrangement of support members co-operating with said support members defining said first seat to support the intermediate member, the intermediate member includes an axisymmetric arrangement of support members defining said second seat, and the stylus holder includes an axisymmetric arrangement of support members co-operating with the said support members defining the second seat to support the stylus holder.

3. A device according to claim 2, wherein the support members defining the first seat and the support members defining the second seat are arranged alternately in annular succession.

4. A device according to claim 3, wherein in any set of three annularly successive support members included in the intermediate member a first and second member of the set define a pair of convergent surface elements, each of the support members defining the first seat is situated between a said pair of convergent surface elements and co-operates therewith to support the intermediate member, the second and third member of said set define a further pair of convergent surface elements, and each of the support members provided on the stylus holder is situated between a further pair of convergent surface elements for the stylus holder to be supported thereby.

5. A device according to claim 2, wherein the support members included in the intermediate member each comprise respective first cylindrical support surfaces whose axes lie in a common plane, the support members defining the first seat each comprise a second cylindrical support surface, the support members included in the stylus holder each comprise a third cylindrical support surface, wherein the second and third support surfaces are arranged in pairs each having one second and one third said surface arranged adjacent one of the first said surfaces in positions such that the axes of the second and third said surfaces are transverse to the axis of the first said surface, and locating means for locating the intermediate member and the stylus holder against dis-placement in said plane.

6. A device according to claim 5, wherein the axes of said first cylindrical surfaces extend radially from a common axis.

7. A device according to claim 5 or 6, wherein said locating means comprise a first planar spring connected between the base member and the intermediate member and a second planar spring connected between the base member and the stylus holder.

8. A device according to claim 1, wherein said base member comprises a supportable end and a free end and wherein said first seat faces said supportable end, said intermediate member is situated between said first seat and said supportable end, and said stylus holder is situated at the side of the intermediate member remote from said supportable end.

9. A device according to claim 8, wherein said first bias means comprise a compression spring arranged between the intermediate member and said supportable end, and said second bias means comprise a tension spring connected between the stylus holder and the intermediate member.